In recent years, with the advancement in utilization of genetic technology, medical treatment that involves utilization of genes, such as genetic diagnosis or gene therapy, has received attention, and also in the agricultural and livestock industry, a great number of methods involving utilization of genes for breed discrimination and cultivar improvement have been developed. As one kind of technologies utilizing genes, the PCR (Polymerase Chain Reaction) method is widely known. The PCR method is now a critical technology to elucidate the information on biological matters.
In the PCR method, a thermal cycle is applied to solution (reaction mixture) that includes a nucleic acid sequence subjected to amplification (target DNA) and a reagent in order to amplify the target DNA. A thermal cycle is a process to apply two or more stages of temperature to the reaction mixture and to repeat the cycle periodically. In the PCR method, usually two or three stages of temperature are applied in a thermal cycle.
In the PCR method, containers, namely tubes or biological sample reaction chips (biotips), for processing biochemical reaction are generally used. However, the known methods have disadvantageously required a large amount of reagent or other liquids for appropriate reaction, complicated the structure of apparatuses to realize thermal cycles necessary for the reaction, and taken a long period of time for the reaction. Thus, biotips or reaction apparatuses that realize PCR that is accurate, requires a shorter period of time, and uses a minimized amount of reagent and sample, have been desired.
To overcome such disadvantages, JP-A-2009-136250 discloses a biological sample reaction chip in which a reaction mixture and liquid that has a smaller specific gravity than the reaction mixture and is immiscible with the reaction mixture (such as mineral oil, hereinafter referred to as “liquid”) are filled, and a biological sample reaction apparatus that applies thermal cycles by rotating the biological sample reaction chip around the horizontal rotational axis thereby moving the reaction mixture.